Transport on van der Wals Superconductor Heretostructures

Harvard University, Cambridge MA

Investigators

Abstract

Nontechnical Description: Superconductivity is a robust macroscopic quantum state that can be utilized for various modern technological applications based on low energy dissipation and quantum coherence. This project will enable the investigation of emergent quantum phenomena associated with extremely thin crystals of high-temperature superconductors. We will build stacked atomic layers of thin superconductors combined with other atomically thin crystalline materials to form more complex quantum systems for this study. The electronic controllability demonstrated in our low-dimensional device structure allows us to investigate the intriguing interaction between electrons and magnetic field vortices near the transition, leading to quantum device applications based on our discoveries. We will develop a novel experimental method to manipulate our superconductors for stacked device forms to achieve this goal. The diverse functionality achieved by complex device structures enables experimental investigation of electronic, magnetic, and thermal properties of resulting structures. We will also develop a theoretical framework to deepen our understanding of high-temperature superconductivity. The proposed study of atomically thin stacked superconductors will promote our understanding of emergent physical phenomena in quantum materials and offer a platform for building quantum technology. New physical properties discovered in this quantum material system can enable novel device applications, such as electronics and magnetoelectronic superconducting devices. A tight combination of research and educational/outreach activities will raise the next generation of science and engineering leaders. Technical Description: The research focus of this project is investigating emergent physical phenomena near the superconductor-insulator transition in van der Waals (vdW) heterostructures formed by atomically thin high-temperature superconductors (HTSs). Based on our current understanding of fluctuation effects and non-equilibrium states in 2-dimensional (2D) superconductors, we will demonstrate the fabrication of 2D vdW superconductors for hybrid heterostructures to achieve complex and diverse functionalities. We study local electronic compressibility in those systems by employing charge-sensitive graphene nanoribbons on top of atomically thin HTS. We also investigate magneto thermoelectric effects and vortex viscosity in a 2D vortex system near the vicinity of the superconductor insulator transition (SIT) regime. Furthermore, we plan to build double-layer devices for vortex and charge drag experiments for detecting magnetic monopoles and their dynamics to understand the vortex-Cooper pair duality. Finally, we will develop a reliable theoretical framework to understand topological obstruction for splitting Cooper pairs into single electrons in the presence of magnetic monopoles near the SIT. The engineering capability of 2D vdW heterostructures comprised of HTS and a deep understanding of the vortex-Cooper pair duality will result in novel functionalities, leading to research breakthroughs in quantum materials with emergent phenomena. We also integrate a tight combination of research and educational/outreach activities for nurturing the next generation of science and engineering leaders. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.